77 On Oil and Oil-gas. 
Now though this result of the superolefiant 
gas from coal does not accord with any of the 
4 preceding results from oil, it comes much 
nearer them than it does to that from olefiant 
gas. So that it is probable the destructive 
distillation of coal gives the same superolefi- 
ant gas as that of oil; and perhaps the alco- 
holic olefiant gas makes no part of the mix- 
tures in either case. 
May,—1823. 
Some time having elapsed since the above 
paper was read, some additional information 
on the subject may be expected. An excel- 
lent memoir by Dr. Henry, was published in 
the Philos. Trans. for 1821, (see also An. of 
_ Philos. new series vol. 2) on the eriform 
compounds of charcoal and hydrogen, in 
which is given a copious detail of experi- 
ments on oil-gas. These results will be read 
with great interest, more especially by those 
concerned in gas establishments. It may be 
useful to extract from said memoir the first 
